Prop for use in mines



may then be re-erected Patented Mar. 22, 1932 PATENT? OFFICE CYRIL BAGULEY, OF HANWORTH, ENGLAND PROP FOR USE MINES Application filed May 7, 1930, Serial No. 450,497, and in Great Britain May 10, 1929.

This invention relates to an improved prop for use in mines or other places for supporting. the roof or other purposes. I

The'objectof this invention is to providea 5 simple, cheap and effective form of prop which will be substantially rigid in use and capable of withstanding great pressure but which may be readily collapsed at will in order to enable it to beeasily withdrawn and for use again asoften as desired. r 1" v According to my invention the body of a pit prop or the like is composed of parts slidable axially relative to one another and having interposed between them means for moving'them apart and for'bringing them towards each other. V

In carrying my invention into practice it is preferred to employ a length of steel or other suitable tubing of a size and thickness sufficient to support the load to which the prop islikely to be subjected. At the top of the tube is provided a head-piece to engage with the roof or other part. This may be 5 enlarged on its upper surface at the point of contact with the mine roof or the like, or the wooden bearer which is usually interposed between them. A corresponding foot-p ece is provided at the lower end of the steel tube.

The head-piece and'foot-piece may conveniently be. formed as malleable castings of iron or as drop 'forgings or in any'other convenient manner. A. suitable spigot is provided both on the head-piece and the foot-piece to 5 engage in the respective endsof the steel tube which is thus effectively located between them. Alternately the tube ends may engage in arecess in the head and foot piece respectively. The engaging surfaces of the head between them willtend to increase the length of the prop by forcingthe headpiece and foot piece apart; For this purpose the'engaging surfacesmaybe of wedge shape and may'consist of any suitable number of teeth or: wedge like projections on one member which engage with correspond ng inclined surfaces'on the other member. 9

In the simplest and preferred construction the top and bottom ends of the steel tube-are I i provided with a suitable numberof teeth or wedge shaped projections inclined in oppoteeth or wedge shaped projections are formed on the head piece and the foot piece respectively. Means is provided to enable the tubular portion of the prop to be rotated relasite directions to each other. Corresponding tively to the head piece or the foot piece or both for the purpose of expanding and contracting the prop by forcing apart or releasing the head piece and foot piece; For this purpose one or more aperturesmay be formed in the tubular strut at suitable posidesired the tube may be thickened or increased in strength at the position where such holes are made so that the effective strength of the prop may not be reduced. Other means may be employed for rotating the prop such for instance as a pipe grip or wrench thus obviating the necessity of cutting the tube or otherwise reducing its strength. As a further alternative suitable portions of the prop may be expanded or shaped to an hexagonal or other suitable form to enable a spanner or wrench to be applied for the purpose of rotating the tubular portion of the prop.

Suitable means may be employed to lock the parts in the expanded position. Oneisuitable method of doing this consists in forming 785 a series of apertures in the spigot of the head piece or foot pieceor bothand providin g a pin adapted to be passed through a corresponding aperture in the tubular portion of 0 Piece and foot Piece with the steel tube 1 are prop near lts end Careful-1y suitably shaped so that relative movement calculating the angle of the inclined wedge shaped members these may be so designed that the parts will remain efiectively locked in the position to which they are removed to expand the prop without the necessity for employing any separate locking mechanism.

If desired the ends of the tubular portion of the prop may be jumped up or otherwise increased in thickness or cross section to provide an additional bearing surface forthe the J I nected together by suitable links, chains, wireor other flexible connections extending be:-

r tweenithe two portions andjpreferabl'y l'o-j wedge-shaped members which engage with oot piece and head piece respectively. The head piece and the foot piece'may be suitably shaped or formed on their upper, and lower surfaces respectivelyto engage against the wooden backing, and so engaged against the wooden backing as to prevent relativerotation between them. For this purpose the surfaces may be serrated or provided with projections or teeth which will become embedded' in the. woodenvbacking; J The head a piece and foot piece may be conveniently concatedtwithin the; tubular portion ofthe prop. Thisiwill prevent the'p'arts from. becoming dislodged-when the prop is removed and when itis being conveyed from place to place.

' Inorder that my invention may be clearly understoodand. readily carried intoeffect I ,hziveapp'ended heretoa sheet of drawings il- ,lnstratingpembodiments thereof, and wherein: M v I ig. -1 is abroken elevation view showmg prop'in its contracted condition.

Fig. 2Iis a broken elevation View showing the router parts of the'prop separatedfrom each other.,

, Fig.3 is'a brokensectional elevation view of Fig. 1. a a ,.Fi'g..4 is'a sectional plan View;

v Fig.6 is a broken detail sectional elevat'ion view showing a slight modification of the method-of resiliently connecting the uper; and lower parts of the prop."

* ,Fi'g. 6 is a detail -viewshowing in side elec vatio'n a modified propex panding'and contractin jmemberin the blank, and c shows such member bent to tubular form. a I

Referring to the drawings, theembodiment illustrated is suitable for the normal requirements of mine pit props and consists oftwo metaltubesa and 7) between the opposing ends of which is located a metal tube or ring :adapted tobe operated to increase the effecitiv e length ofthe prop. 1 1

Y The members a and b are preferably composed of steel and are, formed with flaredor I votherwise suitably shaped lower and upper nifty e'fianged'outwards, I a

IThe'npp r and lower ends respectively of the tubularmembers a and b are also p'ref-' erably' enlarged in thickness or flared exterfnally as indicated at a and Z)? to provide ampl'e support for the ring a and to enable the or. portion of the: prop to be of'convenient diameter forhandling. The members a, b

7 1, eso,4se

and 0V are held in axial alignment by, aspigot" 7 or tube fitted concentrically withinthem, and threaded, riveted, welded or formed integral with any one of the parts a, b and c,

or resting on a ledge or other suitable supportin the member a or otherwise held in a position which ensures the parts a, b and c being held inaxial alignment butyet permitting the member 0 to be rotated relative to the parts a and b. I

The vannul'amedges of the member 0 are formed with symmetrical elongated arcuate ratchet "like teeth or cams h, and the opposing edgesof the members a and b are correspon'dingly shaped with recesses Vi'to receive the cams h. By this means when'the cams hare yfullyaccommodated in the recesses ithe proper-continuity and solidarity of the prop. is

: efi'ected,' but by rotating the ring crelative to the members a and b the part b is raised from the part a and thereby the pro' becomes, ef-

between walls. The pitch of the cam flike teeth IL, and the corresponding recesses i is such that under normal or excessive pressures the ring 0 will be firmly held in'an v position it maynbeturned to about the axis 0 theprop.

fectively wedged between roo and floor or Any suitable means may be provided for v turningthe rin 0. For instance the external surface of t e ring; can be shaped to recelve a spanner, or when itis integral with the tube 9 it can have tommy bar holes through it. 'As an exampleI have shown a number ofshortradial lugs j extending from thering a and apertured, to receive suitable tools, orada-pted to provide abutments for a. spanner. The ring 0 may be bent froma straight blank as shown in Fig. 6 for example to aring as shown'in'Fig. 7, the ends of the blank, being bent to provide a pair of lugs k through-which a bolt or rivet is passed. v If desired this arrangement can be utilized as a means'of holding the ring a in selected position, by adapting it as asplit collar about the tube '9 andclamping it to 'the sleeve byx adjusting the nut onzthe bolt, passed through the lugsk. The lugs I: provide av projection for striking the ring when it is desired to 1'0- tate it to contract the prop,jor extendit." V

vIf desired the ring 0 may be located nearer 5 the base ofthe prop than the top, or midway.

Also if desired two or more rings 0 and correspondinglydivided parts. of theprop may be'employed with eachprop. In, practice it may be, found {desirable to: 'cover or-shroud the rotary ring to prevent, possibility of finyonda position at which there isa suflicient 7 lengthof contact between the wedge shaped faces to eflicientlyasupport thealoadwithout per square inch.

subjecting the material to too great pressure v In order to normally maintain the parts of the prop connected and yet permit extension and contraction of the prop the parts a and b can be resiliently connected, for instance by a stay rod, chain or cable Z anchored by an eye bolt m or other suitable means to a plate or flange n in one end of the prop, and to an eye bolt 0 secured in like manner to the other end of the prop, one or both of these eye bolts having a compression spring p interposed between its nut g and the appropriate plate or flange a. As an alternative or additional form of resilient connection the ligature Z can contain a coiled tension spring 1" as shown in Fig. 5.

If desired only one annular edge of the ring a can be provided with the cam like teeth kthe other edge and the opposing end of the appropriate part of the prop being flat horizontally.

My improved prop may be cheaply constructed in a form which may be easily applied in mines for supporting the roof or for other purposes and may be arranged to. carry very great loads without the risk of collapse. The prop however may be readily released and withdrawn when desired and when removed may be conveyed to other parts and used again as often as required.

I claim:

1. A pit prop comprising two tubular coaxial body parts, a relatively rotatable tubular member interposed between them, means connecting the two parts and said member against lateral displacement, cam like surfaces on the ends of said interposed member and corresponding surfaces on the opposing ends of the said two body parts, said interposed member being rotatable about the axis of the prop.

2. A pit prop comprising two tubular coaxial body parts, a relatively rotatable tubular member interposed between them, a concentric spigot fitted inside the said two parts and said member to hold them against relative lateral displacement, cam like surfaces on the ends of said interposed member and corresponding surfaces on the opposing ends of the said two body parts, said interposed member being rotatable about the axis of the prop.

3. A pit prop comprising two tubular c0- axial body parts, a relatively rotatable tubular member interposed between them, means connecting the two parts and said member against lateral displacement, cam like surfaces on the ends of said interposed member and corresponding surfaces on the opposing ends of the said two, body parts, said interposed member being rotatable about the axis of the prop, and spring means inside the prop connected to said two body parts so as to press them against said interposed member. I

4. A pit prop comprising two tubular co-' axial body parts, a relatively rotatable tubular member interposed between them, means connecting the two parts and said member against lateral displacement, cam like surfaces on the ends of said interposed member and corresponding surfaces on the opposing ends of the said two body parts, said interposed member being rotatable about the axis of the prop, abutments in said body parts, a ligature connected to said abutments and a spring placing said ligature under tension.

5. A pit prop comprising two tubular co axial body parts, a relatively rotatable tubular member interposed between them, means connecting the two parts and said member against lateral displacement, cam like surfaces on the ends of said interposed member and corresponding surfaces on the opposing ends of the said two body parts, said interposed member being rotatable about the axis of the prop, abutments in said body parts, a ligature connected to said abutments and a spring placing said ligature under tension, said spring meanshaving associated with it means for adjusting said tension.

6. A pit prop comprising two tubular coaxial body parts, a relatively rotatable tubular member interposed between them, means connecting the two parts and said member against lateral displacement, cam like surfaces on the ends of said interposed member and corresponding surfaces on the opposing ends of the said two body parts, said interposed member being rotatable about the axis of the prop, abutments in said body parts, a ligature connected to said abutments and a spring placing said ligature under tension, and said interposed member being formed with means whereby it can be rotated with the aid of a tool.

7. In a pit prop a pair of coaxially aligned prop body parts, a relatively rotatable coaxial member between them against which member the pair of prop body parts are adapted to press in opposite directions, and a set of cam like projections on said intermediate member and on one of said prop body parts seating against each other whereby rotation of said intermediate member will effect axial separation of the two prop body 

